CVE-2026-45339Public exploitNetwork attack vector

Authenticated endpoint access via alternate API key header

Published May 15, 2026 · Updated May 15, 2026

Incorrect authorization in Open WebUI before 0.9.0 allows remote authenticated users to access restricted API endpoints via x-api-key. The Anthropic-compatible authentication path accepts the same key from x-api-key but skips the endpoint-allowlist check applied to Authorization credentials. Exploitation requires a valid API key and enabled endpoint restrictions; it grants the key access to otherwise denied API functions, including model processing.

CVSS severity6.5
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in Open WebUI before 0.9.0 allows remote authenticated users to access restricted API endpoints via x-api-key. The Anthropic-compatible authentication path accepts the same key from x-api-key but skips the endpoint-allowlist check applied to Authorization credentials. Exploitation requires a valid API key and enabled endpoint restrictions; it grants the key access to otherwise denied API functions, including model processing.

The record

CVE
CVE-2026-45339
Published
May 15, 2026
Updated
May 15, 2026
Vendor
Open WebUI
Product
Open WebUI
Classifications
CWE-863, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. May 15, 2026CVE publishedPublication date reported by the CVE source.
  2. May 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Open WebUI · Open WebUIversion=< 0.9.0

Published CVSS scores

6.5Open WebUICVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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